The present invention relates to multi-featured power management apparatus and related methods, and more particularly, to multi-featured programmable power converters battery chargers and power management apparatus. Even more particularly, the present invention relates to a universal power management system, using a variable buck/boost converter which can be programmed to provide constant output voltage within a near-universal selection range or a constant current output within a universal selection range, accepting near-universal DC and AC input.
A few examples of the thousands of devices that operate from either rechargeable (secondary) or non-rechargeable (primary) batteries include: cellular phones, cordless drills, hand-held radios, notebook computers, video cameras, military radios, and other application specific instruments. Typically, devices requiring rechargeable batteries are sold with accessory battery chargers that are useful only for a specific device type. Often the accessory battery charger is only useful for a specific device, from a specific manufacturer.
Typical functions desired from any power management device include, but are not limited to, the ability to accept variable input power; accepting standard AC or DC voltage input; sensing battery temperature during a charge cycle; and providing a selectable near universal and constant output voltage which is compatible with a selected target device; providing a selectable, near universal constant output current while charging a battery; and providing a secure connection between the power management device and the selected target battery or device to be charged or powered. Other desirable functions of power management devices include, battery diagnostics, battery reconditioning, multiple backup charge cut-off methods, programmable output voltages or currents, and an ability to display information pertaining to charging and conversion processes.
Most commonly available DC voltages range from about 3 VDC to 30 VDC and most commonly available AC voltages are near 115 VAC or 230 VAC. There is no known power manager, power converter or battery charger that accepts all of these ranges of input voltages while simultaneously providing a wide range of programmable constant output voltages e.g., 2 VDC to 30 VDC or constant output currents, e.g., 0.01 ADC to 2 ADC, efficiently, with compact solid-state hardware. There is a need in the industry for a self-contained, multi-featured, robust, universal power manager that has high selectivity resolution for providing a high resolution selectable current output (on the order of 0.01 ADC resolution) for providing a constant high resolution voltage output (on the order of 0.01 VDC resolution) and while accepting a wide range of input voltages with compact solid-state electronics in an easily programmed fashion for performing the multiple desired operations listed above.
Prior approaches in the art to the above problems have been severely limited. Some approaches which have either constant current output or an output following a characteristic current curve, are not generally selectable or programmable and must be redesigned for different inputs and outputs.
Other approaches do not provide the necessary resolution to accept universal input voltage and provide universal output voltage, or do not provide constant current in battery charging operations and are also not programmable.
For example, multi-pole switches do not operate efficiently with more than eight or ten resistors. Thus, prior art devices employing switches to switch resistors into a resistive voltage divider in order to select an output voltage are severely limited in resolution. Similarly, most microprocessors with built in A-to-D and D-to-A converters have resolutions of only eight bits (256 discrete values). This low resolution is inadequate for providing a constant current supply for battery recharging in the same device as provides high resolution constant output voltages over a wide range.
Consequently, there is also a need in the field of power management (e.g., of battery charging and power conversion) for a universal power management device that allows a user to program a wide range of regulated (constant) output currents and voltages with high resolution, to be supplied in response to a wide-ranging variable (unregulated) input voltage, and for enabling a plurality of operations by the universal power manager.
Similarly, since batteries and devices typically have custom adapters or battery chargers or alternative power sources, and since no known adapter allows near universal electrical connection to a wide variety of battery packs and device terminals, there is also a need for a power manager providing a terminal adapter and cable set allowing easy and reliable connection to a vast majority of batteries and battery powered devices.
Presently, most battery chargers and power converters do not come equipped with a sealed and hardened enclosure, thus making them susceptible to damage from rust and moisture when left outdoors and making them vulnerable to mechanical damage due to rough treatment. Thus, there is a further need in the field for such a device, which is able to withstand harsh environmental conditions, such as those in the field, as well as addressing the other above needs.
The present invention advantageously addresses the above and other needs.